Engine Technology

[Worlds Fastest Comanche]

I have a Mj with a blown up 4 cylinder, and was thinking about using it for a daily driver. Its a 5 speed. I was looking at my options, rebuild the 4 banger for $1,200-$1,500, swap in a 4.0 which would probably cost me the same or more.

because it is a driver, one of the main concerns is fuel economy. I would be willing to spend more on the engine swap and make up fir the additional cost be the increased fuel economy.

 

SO i started looking for an engine that had more hp than my existing 4 banger, got better fuel economy and was really cheap in the boneyards. My first canidate was an ecotec, several versions avaiable, generally the 2.4L was rated around 170 hp and 162 ft/lbs of torque, so more hp the he jeep motor, a little more torque, but no match for the 200 ft/lbs of the 4.0 Probably would be great on gas and a 260hp version is available they used in the Cobalt SS. So i could put a stock motor in to start , the put a turbo motor in later.

 

Canidate #2 is the Colorodo 4 banger, either the 2.8 or 2.9 180 hp on the 2.9, close to the stock 4.0 in hp

 

 

A little more torque than the Ecotec, but no turbo version available. The cool thing is that is it is the smallest menber of the GM Atlas family , so a 5 and 6 cylinder are available. here is a curve on the 5 banger.

 

 

 

More hp than a stock 4.0 and probably better mileage. The colorodo uses a asin trans so the bellhousing might bolt up, the only other hurdle would be a custom harness for the ECM .

[comanche12]

get subaru engine.... ;) justkidding. my little 2.5l flat four made more hp and tq than top one engine

[89er]

Be careful of the 2.9 chevy, I had a 07 colorado before my 89 comanche. the gas milage was around 23-24 tops and the 4 banger made it's usable hp higher so it would lug in 5th with any kind of load. To make it worse I put 16" h-3 rims and 265 tires and it REALLY lugged on the hwy a legal speeds. I was shocked by the low end of my 4L and get 20 mph with my 5 spd. To run anything bigger than a stock tire I think you would be disappointed and if you changed the gears to have power then no mpg. They are great motors I never had a bit of trouble but wished I had the 5cyl. Good luck and keep us posted. :cheers:

[Eagle]

What year is the blown-up MJ engine?

 

If it were me and my truck, I'd put in a late model XJ 4-banger, the one with multi-port injection, and build the engine with a Mopar Stage II camshaft (maybe even a Stage III, but I already have a stage II). There's a NAXJA member from one of the Rockie Mountain states who told me he routinely gets 28 MPG out of his 4-cyl 5-speed XJ. I think he said he was running the Stage III cam but I don't remember the details.

[dasbulliwagen]

MOPAR no longer makes or carries the performance cams for the 2.5. I checked with our dealer parts dept to see if anyone had any laying around on the shelves around the country, NOPE! The only other place Ive found to list a cam for the 2.5 has their website saying they are closed down temporarily... like till 2012. They are in Vancouver somewhere. can't remember the name right now... have the info on the comp at work though if you want it. Another consideration for a newer 4 banger is the 2.4 that came in the Wrangler for a couple years... same engine as the Neon, and TONS of performance parts available.... and you could just swap the trans from the wrangler too. The Chevy 4, 5, and 6 bangers Ive heard nothing but bad things about them.... from GM dealer tech! I would stay away from those. Not sure about the power and torque from the 2.4, but can't be any worse than the original 2.5! Slap a cam in it, and a header.... who knows. You could even swap in a turbo. Have you ever driven a Neon or Caliber SRT4???? SCARY FAST! ( mostly because of horrible torque steer) Good luck. Let us know what you end up doing!

[Worlds Fastest Comanche]

Here is a HP curve for a 2.5

 

 

looks like about 130 ft/lbs wouls be the generally available torque The ecotec would have about 160 ft/lbs and the atlas 175-185ft/lbs. I think the Canyon was geared more for gas mileage than for performance. I am not sure what my rear end gear ratio is, but i think it is a 4.10. a ratio like this or shorter would put the engine mor in to the power band.

 

As i said at the start, i could rebuild the 4, or put in a 6, but i can find Ecotec engines with 60,000-70,000 miles on them for $450-$500. Even a boneyard 2.5 seems to be $800- $1,000 At $500 per engine the ecotecs are almost disposable.

[Eagle]

... the ecotecs are almost disposable.

Did you read what you wrote there?

 

I have no doubt you can get a newer 4-banger that makes more power on paper, and may even make more power in the real world. But those engines are in much lighter vehicles, so they won't perform in an MJ like they do in their "native" vehicles, nor will they produce the gas mileage in an MJ that they do in their native vehicles. An MJ 2.5L is good for between 200k and 300k miles, and I don't see any of the newer "disposable" engines being good for anywhere near that.

 

I'd go with the Jeep engine.

[Worlds Fastest Comanche]

Well seing how you are the " Self-appointed President for Life of the International MJ Preservation Society" your opinion may be somewhat biased.

 

AN empty MJ is really not that heavy , i suspect some where in the 3,400 lb range. (2wd, which is what i have) I think the weight is similar to the HHR which comes standard with a Ecotec. The Cobalt is probably around 2,800lbs, but put a couple of fat people in ti and you could get close to the weight of an MJ.

 

I think I am going to give it a try, the Ecotec gets 35mpg highway in a Cobalt, if i get anything over 25 in an MJ i would be happy.

 

The Ecotec probably will not last 250,000 miles, but i can't remember the last vehicle i owned for 250,000 miles.

 

The stated goals are better gas mileage and more power.

[freakjeep93]

i would like to see the possiblity of either the SS motor or the colorado 5 cyl.

[Joop]

Thought about volvo "whiteblock's"?? The 960 i6 use a AW30-40 transmission that is basicly a rearwheel drive AW4. This means that it should be possible to match up any volvo aluminium 4, 5 or 6 cylinder to a AW4 using the bellhousing, converter etc of a AW30-40. don't know anything about the volvo 4bangers, but the N/A i5's range is from 2.0 126hp to 2.5 170hp. Turbos goes from 2.0 180hp to the latest models, (including ford focus) with 2.5 over 300hp. I6 models has a power range pretty much the same as the i5, but probably a little more torque because of more dispacement.

 

My 850 have rolled 361000km at the moment, and it still purrs like a cat. During the 62000km I have driven it I have never had any trouble at all. Did a compression test a month ago and it was well within factory specs. In my opinion theres not many, if any, engine makers out the that makes longer lasting engines than volvo. Did a lot of research about this some time ago, simply because I am as much a volvofreak as I am a jeep addict and maybe someday, if I ever get too much time and money, Ill put a T6 or T5 in a XJ/MJ just for the fun of it. :dunce:

[Worlds Fastest Comanche]

The 3.0 and 3.2L Volvo inline 6 motors used on the XC70 (US Model name) seem like great engines. Either one has more hp than a stock 4.0 and the torbocharged 3.0 is about 300 hp.

 

The problen in the US is that Volvo parts are very expensive in wrecking yards (junk yards), not much is know about the ECM and how to rewire or reprogram it for an different vehicle. The transmission bolt pattern is not known either, if a bellhousing exists or a adapter plate is made by sombody it would be great.

 

I did find 2 motors in junk yards, A turbo motor for $2,500 and a non turbo motor with 56,000 miles for $2,600. The chevy Atlas 4200 (290hp) can be had for about $800 in junkyards. I would assume that in norway that US car parts go for a priemum.

 

I did have an interest in the Volvo 3.0 for my land speed Comanche, they have a 3.0L class and this seemed like a good canidate to run in the blown class. I did not persue it because i could not find any information on a RWD transmission that would bolt up or if a ASIN bellhousing was avaiable

[Eagle]

Well seing how you are the " Self-appointed President for Life of the International MJ Preservation Society" your opinion may be somewhat biased.

Hey! I resemble that remark!

 

And you are correct. I am definitely biased in favor of AMC engines over the throw-away crap they produce today. I don't regard maximum horsepower as the holy grail of engine design. I prefer simplicity and longevity.

[Oizarod115]

The 3.0 and 3.2L Volvo inline 6 motors used on the XC70 (US Model name) seem like great engines. Either one has more hp than a stock 4.0 and the torbocharged 3.0 is about 300 hp.

 

The problen in the US is that Volvo parts are very expensive in wrecking yards (junk yards), not much is know about the ECM and how to rewire or reprogram it for an different vehicle. The transmission bolt pattern is not known either, if a bellhousing exists or a adapter plate is made by sombody it would be great.

 

I did find 2 motors in junk yards, A turbo motor for $2,500 and a non turbo motor with 56,000 miles for $2,600. The chevy Atlas 4200 (290hp) can be had for about $800 in junkyards. I would assume that in norway that US car parts go for a priemum.

 

I did have an interest in the Volvo 3.0 for my land speed Comanche, they have a 3.0L class and this seemed like a good canidate to run in the blown class. I did not persue it because i could not find any information on a RWD transmission that would bolt up or if a ASIN bellhousing was avaiable

 

woahhhh nelly. careful where you tread over there in volvo-land. you don't want a t6 volvo motor, or the whiteblock 6's at all. the 5 cyl is a VERY good motor, especially the low pressure 2.3 turbo, but all of the aluminum volvo motors start to burn at 150+ and not much at all you can do to fix it.

[ratrapp]

you'll really start getting into the money when you start swapping from a non jeep drivetrain.nothing is as easy as it seems and always cost more.not saying anything isn't possible but the extra few mpg's you may get is going to take along time to recoup from money spent on the swap.just my two cents.i would just rebuild the 2.5 and be done with it.

[TrailReadyMJ]

 

AN empty MJ is really not that heavy , i suspect some where in the 3,400 lb range. (2wd, which is what i have) I think the weight is similar to the HHR which comes standard with a Ecotec. The Cobalt is probably around 2,800lbs, but put a couple of fat people in ti and you could get close to the weight of an MJ.

Yes' these are LIGHT trucks! Remember these are uni-body trucks, and they actually weigh less than a full frame wrangler! A 4.0 TJ has a curb weight of 3229lbs. A 4.0, 4x4, MJ has a curb weight of only 3090Lbs!

 

A 2009, 4dr cobalt ls, with auto trans has a curb weight of 3216, so it actually weights MORE than an MJ!!!

 

I have had mine on scales at the steelyard, and with all current mods (heavy bumpers, rockers, 35" swampers, loaded toolbox, etc...) and me in the cab (180lbs), it still only weighs 4100Lbs. I had it loaded down to 6520 going in! :eek: Poor truck, at least it was short trip! It handled it pretty good though considering I had about a ton in the bed!

 

Remember, they have had to add a lot of extra weight to vehicles in general over the years due to safety requirements, and other various reasons such as quieter interiors. In general, 80s vehicles are known to be tin cans! They used thinner steel compared to older vehicles, FSJs for example, but didn't have all the extra bracing and plush, quiet interiors, they do today.

[Red 1989 MJ]

My humble opinion is to stick with jeep motor.

 

You could find a good 2.5 in JY for less money than a swap.

 

I don't think your economy on MPG will egal the investment. :thumbsup:

[johnj92131]

Re: MJ weight:

 

My 91 two wheel drive has an I6, long bed, automatic, Dana 44, SnugTop, bed liner, heavy rubber load mat. With 2 large adults (son & I). Last time I was on a scale, weight was 3800 lbs.

 

Re: fuel economy:

 

If you want an engine for fuel economy, look at a VW TDI engine. The stock 1.9 TDI engine has 90 hp and 150 lbs/ft. Modifications are widely available that can take power to 200 hp and Tq to 300lb/ft. My 96 Passat wagon is 31-3200 lbs, gets 38-40 mpg on short trips around town and well over 40 on the road (48.8 last time).

[Worlds Fastest Comanche]

Re: MJ weight:

 

My 91 two wheel drive has an I6, long bed, automatic, Dana 44, SnugTop, bed liner, heavy rubber load mat. With 2 large adults (son & I). Last time I was on a scale, weight was 3800 lbs.

 

Re: fuel economy:

 

If you want an engine for fuel economy, look at a VW TDI engine. The stock 1.9 TDI engine has 90 hp and 150 lbs/ft. Modifications are widely available that can take power to 200 hp and Tq to 300lb/ft. My 96 Passat wagon is 31-3200 lbs, gets 38-40 mpg on short trips around town and well over 40 on the road (48.8 last time).

 

Is that a diesel?

[Oizarod115]

yeah, TDI, turbo diesel

[Worlds Fastest Comanche]

yeah, TDI, turbo diesel

 

 

Probably the eaiest way to go diesel would be to get a motor from an 85 or 86 diesel Xj or MJ. Might be hard to find.

[Pete M]

there's nothing impressive about the old diesels. :ack: they were anemic and parts can be very hard to come by.

[kro10000]

IMO the factory XJ/MJ diesel was a POS. Unreliable, a pain to maintain, and no parts availability. Also the 1.9 TDI is too complex for my tastes. I think an ecotech MJ would be pretty cool though

[Worlds Fastest Comanche]

IMO the factory XJ/MJ diesel was a POS. Unreliable, a pain to maintain, and no parts availability. Also the 1.9 TDI is too complex for my tastes. I think an ecotech MJ would be pretty cool though

 

 

WOW 1 person beside me thinks it would be cool! I thought NOBODY was going to like the idea! Maybe after i get it together i can get some more converts.

[johnj92131]

yeah, TDI, turbo diesel

 

 

Probably the eaiest way to go diesel would be to get a motor from an 85 or 86 diesel Xj or MJ. Might be hard to find.

 

The VW TDI (Turbo Direct Injection) is 2 generations newer than the Renault engine in the 85-86 XJ/MJ. Many, many more of them in the states. Adaptor kit exists foa a TDI to Toyota transmission (Acme adapters). Also much less loud than the old Renault. To top it off, it is much lighter. But you will not buy a 1.9 TDI for $500.00 - then again, it is not a throw-a-way engine. 300-500K miles is not unusual. I have 203K on mine.

[Worlds Fastest Comanche]

 

The VW TDI (Turbo Direct Injection) is 2 generations newer than the Renault engine in the 85-86 XJ/MJ. Many, many more of them in the states. Adaptor kit exists foa a TDI to Toyota transmission (Acme adapters). Also much less loud than the old Renault. To top it off, it is much lighter. But you will not buy a 1.9 TDI for $500.00 - then again, it is not a throw-a-way engine. 300-500K miles is not unusual. I have 203K on mine.

 

 

I was looking at the HP numnbers for that engine, seem pretty low. What is the actual spec?